Please note that eDoc will be permanently shut down in the first quarter of 2021!      Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents



ID: 308673.0, MPI für Astronomie / Publikationen_mpia
Hot organic molecules toward a young low-mass star: A look at inner disk chemistry
Authors:Lahuis, F.; van Dishoeck, E. F.; Boogert, A. C. A.; Pontoppidan, K. M.; Blake, G. A.; Dullemond, C. P.; Evans, N. J.; Hogerheijde, M. R.; Jørgensen, J. K.; Kessler-Silacci, J. E.; Knez, C.
Date of Publication (YYYY-MM-DD):2006
Journal Abbrev.:The Astrophysical Journal
Volume:636
Start Page:L145
End Page:L148
Audience:Not Specified
Abstract / Description:Spitzer Space Telescope spectra of the low-mass young stellar object (YSO) IRS 46 (Lbol~0.6 Lsolar) in Ophiuchus reveal strong vibration-rotation absorption bands of gaseous C2H2, HCN, and CO2. This is the only source out of a sample of ~100 YSOs that shows these features, and this is the first time that they are seen in the spectrum of a solar-mass YSO. Analysis of the Spitzer data combined with Keck L- and M-band spectra reveals excitation temperatures of >~350 K and abundances of 10-6 to 10-5 with respect to H2, orders of magnitude higher than those found in cold clouds. In spite of this high abundance, the HCN J=4-3 line is barely detected with the James Clerk Maxwell Telescope (JCMT), indicating a source diameter less than 13 AU. The (sub)millimeter continuum emission and the absence of scattered light in near-infrared images limit the mass and temperature of any remnant collapsing envelope to less than 0.01 Msolar and 100 K, respectively. This excludes a hot-core-type region as found in high-mass YSOs. The most plausible origin of this hot gas rich in organic molecules is in the inner (<6 AU radius) region of the disk around IRS 46, either the disk itself or a disk wind. A nearly edge-on two-dimensional disk model fits the spectral energy distribution (SED) and gives a column of dense warm gas along the line of sight that is consistent with the absorption data. These data illustrate the unique potential of high-resolution infrared spectroscopy to probe the organic chemistry, gas temperatures, and gas kinematics in the planet-forming zones close to a young star.
Free Keywords:Infrared: ISM; ISM: individual (IRS 46); ISM: Jets and Outflows; ISM: Molecules; Stars: Planetary Systems: Protoplanetary Disks; Stars: Formation
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi...
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.